Merge branch 'master' into refactor/RootPrecision

Author: alxkm

src/main/java/com/thealgorithms/dynamicprogramming/FordFulkerson.java

@@ -2,76 +2,54 @@
 
 import java.util.LinkedList;
 import java.util.Queue;
-import java.util.Vector;
 
 public final class FordFulkerson {
-    private FordFulkerson() {
-    }
-
-    static final int INF = 987654321;
-    // edges
-    static int vertexCount;
-    static int[][] capacity;
-    static int[][] flow;
+    private static final int INF = Integer.MAX_VALUE;
 
-    public static void main(String[] args) {
-        System.out.println("Vertex Count : 6");
-        vertexCount = 6;
-        capacity = new int[vertexCount][vertexCount];
-
-        capacity[0][1] = 12;
-        capacity[0][3] = 13;
-        capacity[1][2] = 10;
-        capacity[2][3] = 13;
-        capacity[2][4] = 3;
-        capacity[2][5] = 15;
-        capacity[3][2] = 7;
-        capacity[3][4] = 15;
-        capacity[4][5] = 17;
-
-        System.out.println("Max capacity in networkFlow : " + networkFlow(0, 5));
+    private FordFulkerson() {
     }
 
-    private static int networkFlow(int source, int sink) {
-        flow = new int[vertexCount][vertexCount];
+    public static int networkFlow(int vertexCount, int[][] capacity, int[][] flow, int source, int sink) {
         int totalFlow = 0;
+
         while (true) {
-            Vector<Integer> parent = new Vector<>(vertexCount);
-            for (int i = 0; i < vertexCount; i++) {
-                parent.add(-1);
-            }
-            Queue<Integer> q = new LinkedList<>();
-            parent.set(source, source);
-            q.add(source);
-            while (!q.isEmpty() && parent.get(sink) == -1) {
-                int here = q.peek();
-                q.poll();
-                for (int there = 0; there < vertexCount; ++there) {
-                    if (capacity[here][there] - flow[here][there] > 0 && parent.get(there) == -1) {
-                        q.add(there);
-                        parent.set(there, here);
+            int[] parent = new int[vertexCount];
+            boolean[] visited = new boolean[vertexCount];
+            Queue<Integer> queue = new LinkedList<>();
+
+            queue.add(source);
+            visited[source] = true;
+            parent[source] = -1;
+
+            while (!queue.isEmpty() && !visited[sink]) {
+                int current = queue.poll();
+
+                for (int next = 0; next < vertexCount; next++) {
+                    if (!visited[next] && capacity[current][next] - flow[current][next] > 0) {
+                        queue.add(next);
+                        visited[next] = true;
+                        parent[next] = current;
                     }
                 }
             }
-            if (parent.get(sink) == -1) {
-                break;
+
+            if (!visited[sink]) {
+                break; // No more augmenting paths
             }
 
-            int amount = INF;
-            String printer = "path : ";
-            StringBuilder sb = new StringBuilder();
-            for (int p = sink; p != source; p = parent.get(p)) {
-                amount = Math.min(capacity[parent.get(p)][p] - flow[parent.get(p)][p], amount);
-                sb.append(p + "-");
+            int pathFlow = INF;
+            for (int v = sink; v != source; v = parent[v]) {
+                int u = parent[v];
+                pathFlow = Math.min(pathFlow, capacity[u][v] - flow[u][v]);
             }
-            sb.append(source);
-            for (int p = sink; p != source; p = parent.get(p)) {
-                flow[parent.get(p)][p] += amount;
-                flow[p][parent.get(p)] -= amount;
+
+            for (int v = sink; v != source; v = parent[v]) {
+                int u = parent[v];
+                flow[u][v] += pathFlow;
+                flow[v][u] -= pathFlow;
             }
-            totalFlow += amount;
-            printer += sb.reverse() + " / max flow : " + totalFlow;
-            System.out.println(printer);
+
+            totalFlow += pathFlow;
         }
 
         return totalFlow;

src/main/java/com/thealgorithms/others/LowestBasePalindrome.java

@@ -1,6 +1,7 @@
 package com.thealgorithms.others;
 
 import java.util.ArrayList;
+import java.util.List;
 
 /**
  * @brief Class for finding the lowest base in which a given integer is a palindrome.
@@ -10,58 +11,74 @@ public final class LowestBasePalindrome {
     private LowestBasePalindrome() {
     }
 
+    /**
+     * Validates the base, ensuring it is greater than 1.
+     *
+     * @param base the base to be checked
+     * @throws IllegalArgumentException if the base is less than or equal to 1
+     */
     private static void checkBase(int base) {
         if (base <= 1) {
-            throw new IllegalArgumentException("base must be greater than 1.");
+            throw new IllegalArgumentException("Base must be greater than 1.");
         }
     }
 
+    /**
+     * Validates the number, ensuring it is non-negative.
+     *
+     * @param number the number to be checked
+     * @throws IllegalArgumentException if the number is negative
+     */
     private static void checkNumber(int number) {
         if (number < 0) {
-            throw new IllegalArgumentException("number must be nonnegative.");
+            throw new IllegalArgumentException("Number must be non-negative.");
         }
     }
 
     /**
-     * @brief computes the representation of the input number in given base
-     * @param number the input number
-     * @param base the given base
-     * @exception IllegalArgumentException number is negative or base is less than 2
-     * @return the list containing the digits of the input number in the given base, the most
-     *     significant digit is at the end of the array
+     * Computes the digits of a given number in a specified base.
+     *
+     * @param number the number to be converted
+     * @param base the base to be used for the conversion
+     * @return a list of digits representing the number in the given base, with the most
+     *         significant digit at the end of the list
+     * @throws IllegalArgumentException if the number is negative or the base is less than 2
      */
-    public static ArrayList<Integer> computeDigitsInBase(int number, int base) {
+    public static List<Integer> computeDigitsInBase(int number, int base) {
         checkNumber(number);
         checkBase(base);
-        var result = new ArrayList<Integer>();
+
+        List<Integer> digits = new ArrayList<>();
         while (number > 0) {
-            result.add(number % base);
+            digits.add(number % base);
             number /= base;
         }
-        return result;
+        return digits;
     }
 
     /**
-     * @brief checks if the input array is a palindrome
-     * @brief list the input array
-     * @return true, if the input array is a palindrome, false otherwise
+     * Checks if a list of integers is palindromic.
+     *
+     * @param list the list of integers to be checked
+     * @return {@code true} if the list is a palindrome, {@code false} otherwise
      */
-    public static boolean isPalindromic(ArrayList<Integer> list) {
-        for (int pos = 0; pos < list.size() / 2; ++pos) {
-            if (list.get(pos) != list.get(list.size() - 1 - pos)) {
+    public static boolean isPalindromic(List<Integer> list) {
+        int size = list.size();
+        for (int i = 0; i < size / 2; i++) {
+            if (!list.get(i).equals(list.get(size - 1 - i))) {
                 return false;
             }
         }
         return true;
     }
 
     /**
-     * @brief checks if representation of the input number in given base is a palindrome
-     * @param number the input number
-     * @param base the given base
-     * @exception IllegalArgumentException number is negative or base is less than 2
-     * @return true, if the input number represented in the given base is a palindrome, false
-     *     otherwise
+     * Checks if the representation of a given number in a specified base is palindromic.
+     *
+     * @param number the number to be checked
+     * @param base the base in which the number will be represented
+     * @return {@code true} if the number is palindromic in the specified base, {@code false} otherwise
+     * @throws IllegalArgumentException if the number is negative or the base is less than 2
      */
     public static boolean isPalindromicInBase(int number, int base) {
         checkNumber(number);
@@ -72,24 +89,26 @@ public static boolean isPalindromicInBase(int number, int base) {
         }
 
         if (number % base == 0) {
-            // the last digit of number written in base is 0
+            // If the last digit of the number in the given base is 0, it can't be palindromic
             return false;
         }
 
         return isPalindromic(computeDigitsInBase(number, base));
     }
 
     /**
-     * @brief finds the smallest base for which the representation of the input number is a
-     * palindrome
-     * @param number the input number
-     * @exception IllegalArgumentException number is negative
-     * @return the smallest base for which the representation of the input number is a palindrome
+     * Finds the smallest base in which the representation of a given number is palindromic.
+     *
+     * @param number the number to be checked
+     * @return the smallest base in which the number is a palindrome
+     * @throws IllegalArgumentException if the number is negative
      */
     public static int lowestBasePalindrome(int number) {
+        checkNumber(number);
+
         int base = 2;
         while (!isPalindromicInBase(number, base)) {
-            ++base;
+            base++;
         }
         return base;
     }

src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java

@@ -1,63 +1,44 @@
 package com.thealgorithms.others;
 
-/* Program to reverse a Stack using Recursion*/
 import java.util.Stack;
 
+/**
+ * Class that provides methods to reverse a stack using recursion.
+ */
 public final class ReverseStackUsingRecursion {
     private ReverseStackUsingRecursion() {
     }
 
-    // Stack
-    private static Stack<Integer> stack = new Stack<>();
-
-    // Main function
-    public static void main(String[] args) {
-        // To Create a Dummy Stack containing integers from 0-9
-        for (int i = 0; i < 10; i++) {
-            stack.push(i);
-        }
-        System.out.println("STACK");
-
-        // To print that dummy Stack
-        for (int k = 9; k >= 0; k--) {
-            System.out.println(k);
+    /**
+     * Reverses the elements of the given stack using recursion.
+     *
+     * @param stack the stack to be reversed
+     * @throws IllegalArgumentException if the stack is null
+     */
+    public static void reverse(Stack<Integer> stack) {
+        if (stack == null) {
+            throw new IllegalArgumentException("Stack cannot be null");
         }
-
-        // Reverse Function called
-        reverseUsingRecursion(stack);
-
-        System.out.println("REVERSED STACK : ");
-        // To print reversed  stack
-        while (!stack.isEmpty()) {
-            System.out.println(stack.pop());
+        if (!stack.isEmpty()) {
+            int topElement = stack.pop();
+            reverse(stack);
+            insertAtBottom(stack, topElement);
         }
     }
 
-    // Function Used to reverse Stack Using Recursion
-    private static void reverseUsingRecursion(Stack<Integer> stack) {
-        if (stack.isEmpty()) { // If stack is empty then return
-            return;
-        }
-        /* All items are stored in call stack until we reach the end*/
-
-        int temptop = stack.peek();
-        stack.pop();
-        reverseUsingRecursion(stack); // Recursion call
-        insertAtEnd(temptop); // Insert items held in call stack one by one into stack
-    }
-
-    // Function used to insert element at the end of stack
-    private static void insertAtEnd(int temptop) {
+    /**
+     * Inserts an element at the bottom of the given stack.
+     *
+     * @param stack    the stack where the element will be inserted
+     * @param element  the element to be inserted at the bottom
+     */
+    private static void insertAtBottom(Stack<Integer> stack, int element) {
         if (stack.isEmpty()) {
-            stack.push(temptop); // If stack is empty push the element
+            stack.push(element);
         } else {
-            int temp = stack.peek();
-            /* All the items are stored in call stack until we reach end*/
-            stack.pop();
-
-            insertAtEnd(temptop); // Recursive call
-
-            stack.push(temp);
+            int topElement = stack.pop();
+            insertAtBottom(stack, element);
+            stack.push(topElement);
         }
     }
 }

src/main/java/com/thealgorithms/others/TwoPointers.java

@@ -1,39 +1,33 @@
 package com.thealgorithms.others;
 
-import java.util.Arrays;
-
 /**
- * The two pointer technique is a useful tool to utilize when searching for
+ * The two-pointer technique is a useful tool to utilize when searching for
  * pairs in a sorted array.
  *
  * <p>
- * link: https://www.geeksforgeeks.org/two-pointers-technique/
+ * Link: https://www.geeksforgeeks.org/two-pointers-technique/
  */
 final class TwoPointers {
     private TwoPointers() {
     }
 
     /**
-     * Given a sorted array arr (sorted in ascending order). Find if there
-     * exists any pair of elements such that their sum is equal to key.
+     * Given a sorted array arr (sorted in ascending order), find if there exists
+     * any pair of elements such that their sum is equal to the key.
      *
-     * @param arr the array contains elements
+     * @param arr the array containing elements (must be sorted in ascending order)
      * @param key the number to search
-     * @return {@code true} if there exists a pair of elements, {@code false}
-     * otherwise.
+     * @return {@code true} if there exists a pair of elements, {@code false} otherwise.
      */
     public static boolean isPairedSum(int[] arr, int key) {
-        /* array sorting is necessary for this algorithm to function correctly */
-        Arrays.sort(arr);
-        int i = 0;
-        /* index of first element */
-        int j = arr.length - 1;
-        /* index of last element */
+        int i = 0; // index of the first element
+        int j = arr.length - 1; // index of the last element
 
         while (i < j) {
-            if (arr[i] + arr[j] == key) {
+            int sum = arr[i] + arr[j];
+            if (sum == key) {
                 return true;
-            } else if (arr[i] + arr[j] < key) {
+            } else if (sum < key) {
                 i++;
             } else {
                 j--;